A number of methods for treating slow-healing wounds, such as infected wounds, diabetes sores, pressure sores or deep wounds, are previously known.
Drainage of, for example, surgical wounds or other weeping wounds with underpressure is a standard treatment which has been used for decades. An example of a manual suction pump for this purpose is described in U.S. Pat. No. 3,742,952.
U.S. Pat. No. 3,572,340 describes a pump in the form of an elastically compressible body made of an open-celled foam material, preferably a polyurethane foam, which body also serves as a receptacle for fluid drained from the wound. The pump is said to have a capacity to maintain an underpressure of 15-80 mmHg for more than 48 hours. A perforated drain is intended to be placed in the wound pocket and is connected to the pump by a tube. A similar device is described in U.S. Pat. No. 4,525,166, in the description of which it is specifically stated that the underpressure not only drains wound fluid but also draws together the wound edges and stimulates tissue growth and healing of the wound. The two latter publications therefore state that vacuum treatment of wounds stimulates wound healing.
The terms vacuum treatment, treatment with reduced pressure and treatment under negative pressure are used interchangeably in the literature. It should be pointed out that, where these terms are used within this description, treatment at a pressure below normal atmospheric pressure is always meant.
Deep wounds have also been treated with a combination of a rinsing fluid supply and subsequent aspiration. Examples of such devices are described in U.S. Pat. No. 5,385,494 and U.S. Pat. No. 4,382,441.
Extensive studies of the effect of both continuous and intermittent treatment of wounds under negative pressure, i.e. pressure below normal atmospheric pressure, were conducted during the 80's in Russian institutions. It was here demonstrated that slow-healing wounds heal substantially faster with the aid of vacuum treatment compared with conventional treatment methods. It was also shown, inter alia, that treatment with reduced pressure produced a significant antibacterial effect. The said Russian studies are described in articles in the Russian medical journal Vestnik Khirurgii. The articles from the said journal are:    1) Kostiuchenok et al, September 1986, pages 18-21.    2) Davydov et al, September 1986, pages 66-70.    3) Usupov et al, April 1987, pages 42-45.    4) Davydov et al, October 1988, pages 48-52.    5) Davydov et al, February 1991, pages 132-135.
In an article by Chariker et al in the journal Contemporary Surgery, issue 34, June 1989, it is stated that vacuum treatment improves the growth of granulation tissue and the wound contraction of wounds which with conventional treatment are very slow-healing.
The vacuum treatment of wounds is also described in U.S. Pat. No. 4,969,880, U.S. Pat. No. 5,645,081 and U.S. Pat. No. 5,636,643.
As examples of applications describing the vacuum treatment of wounds can be cited U.S. Pat. No. 6,855,135 B2 and WO 2006/025848 A2.
Previously known devices for the vacuum treatment of wounds are not satisfactory in all respects. A fundamental problem is that they are quite bulky right in front of the wound, which can result in the wound being able to be subjected by the bulky parts right in front of it to undesirable load stresses, which can be painful for the patient and can disturb the wound healing process. A very major problem is the relatively rigid tubes which connect the wound pocket to the pressure source. The tubes are unwieldy and bulky and can give rise to chafes and, in unfavourable cases, can also cause pressure sores on the patient. Depending on where the patient has the wound, it is often not possible to place the pressure source or an intermediate fluid-receiving receptacle close to the wound, but instead it may be necessary to use relatively long tubes, for example from the foot of the patient right up to the waist, which can cause chafes on patients who are lying or sitting. A further problem with conventional tubes is that it is difficult to achieve satisfactory leak-tightness at the connection between the tube and the sealing film placed over the wound.
If the underpressure for some reason abates, in previously known devices there is a risk of exudate which has previously been aspirated from the wound pocket being transported back and contaminating this, unless a check valve is present at the connection between the tube and the wound pocket.